<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	</head>
	<body>
		<input type="text" src="" value="" id="one" / >
		<tr></tr>
		<select name="qpqpq" id="qpqpq">
			<option value="" id="+">+</option>
			<option value="" id="-">-</option>
			<option value="" id="*">*</option>
			<option value="" id="/">/</option>
		</select>
		<input type="text" src=""  value="" id="two" />
		<button type="button" onclick="uuu()">=</button>
		<input type="text" name id="three" value="" />
	</body>
	<script type="text/javascript" >
		function uuu(){
			var II=parseFloat(document.getElementById('one').value);
			var OO=parseFloat(document.getElementById('two').value);
			var ff=0;
			var qpqpq=document.getElementById('qpqpq');
			var f=qpqpq.selectedIndex;//获取索引
			if(f==0){
				ff=II+OO;
			}else if (f==1){
				ff=II-OO;
			}else if (f==2){
				ff=II*OO;
			}else{
				if(OO!==0)
				ff=II /OO;
			}
			document.getElementById('three').value=ff;
		}
	</script>
</html>
